Radeon HD 4890 2GB vs Radeon HD 6850

Intro

The Radeon HD 4890 2GB comes with a GPU core speed of 1000 MHz, and the 2048 MB of GDDR5 memory runs at 975 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.

Compare all of that to the Radeon HD 6850, which comes with core speeds of 775 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 960 SPUs along with 48 TAUs and 32 Rasterization Operator Units.

Price Comparison

Please note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.

Radeon HD 4890 2GB Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Radeon HD 6850 Amazon.com Other US-based stores Amazon.co.uk Amazon.de Amazon.fr

Specifications

Model	Radeon HD 4890 2GB	Radeon HD 6850
Manufacturer	ATi	ATi
Year	Apr 2, 2009	October 2010
Code Name	RV790 XT	Barts Pro
Fab Process	55 nm	40 nm
Bus	PCIe 2.0 x16	PCIe x16
Memory	2048 MB	1024 MB
Core Speed	1000 MHz	775 MHz
Shader Speed	N/A MHz	(N/A) MHz
Memory Speed	975 MHz	1000 MHz
Unified Shaders	800(160x5)	960
Texture Mapping Units	40	48
Render Output Units	16	32
Bus Type	GDDR5	GDDR5
Bus Width	256-bit	256-bit
DirectX Version	DirectX 10.1	DirectX 11
OpenGL Version	OpenGL 3.0	OpenGL 4.1
Power (Max TDP)	190 watts	127 watts
Shader Model	4.1	5.0
Bandwidth	124800 MB/sec	128000 MB/sec
Texel Rate	40000 Mtexels/sec	37200 Mtexels/sec
Pixel Rate	16000 Mpixels/sec	24800 Mpixels/sec

Memory Bandwidth: Memory bandwidth is the largest amount of information (counted in megabytes per second) that can be transported past the external memory interface in a second. The number is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.

Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.